EMC testing and rectification ideas for medical device products

EMC testing and rectification ideas for medical device products learned in the process of theory and practice .

1. EMC concept

EMC (Electro Magnetic Compatibility) is also called electromagnetic compatibility, or EMC for short. EMC testing is also called electromagnetic compatibility testing. The electromagnetic compatibility test shall meet the relevant industry standards YY xxxx-xxxx. The standard proposes that EMC testing includes electromagnetic emission and electromagnetic immunity . The test content is as follows [1]:

As a qualified medical device product, it needs to meet the requirements of various test items proposed in electromagnetic emission and electromagnetic immunity.

1.1 Electromagnetic emission test

For example, the requirements for Class A products in the national standard GB 4824-2019 are as follows [1]:

1.2 Electromagnetic immunity test

For example, in the industry standard YY 0505-2012, the immunity requirements for equipment are as follows [1]:

1.3 National Standards

The national standard GB/T 17626 proposes 28 specific standards for electromagnetic compatibility testing, testing and measurement technology [2] [3]:

For medical device products with different positioning, the number of tests that need to be completed is different.

2. Corrective measures

2.1 Electromagnetic radiation emission exceeds the standard

For the phenomenon that the product emits excessive electromagnetic radiation to the outside, you can try to solve it from the following aspects:

• Add conductive pads to the gaps in the metal shell of the product to reduce non-electrical continuous gaps and achieve better shell shielding performance. 【1】
• Adding a magnetic ring at the entrance of the power cable into the chassis can realize high-frequency filtering and prevent radio frequency disturbance signals from escaping from the cable. 【1】
• In PCB design, reduce the current loop area that may form an "antenna". One method is to lay a ground wire next to the signal transmission line, and the distance between the two wires is close to reduce the loop area. 【1】

3. References

【1】Yan Tingwei, Song Qingjun, Wang Qingmin, Zhang Yuhua, Xin Ling, Kong Qiangqiang. EMC test and rectification of an electric operating table[J]. Electronic Quality, 2021(07):132-134. 【2】https:
/ /std.samr.gov.cn/gb/gbQuery
【3】https://blog.csdn.net/whik1194/article/details/103223618